Assessment of the NASA Evolve Long-Term Orbital Debris Evolution Model.

Abstract : The EVOLVE long-term orbital debris evolution model developed for the NASA Johnson Space Center by Lockheed Engineering and Sciences Company and Systems Planning Corporation is described and evaluated in detail. This computer model calculates the low earth orbit (LEO) debris spatial number density or flux environment as a function of fragment size, altitude, and time. Launched intact objects, introduced from detailed manifest databases, are time-evolved with an analytical orbit propagator. Debris clouds, formed from the application of cloud formation algorithm and breakup model, are time-evolved using a derived phenomenological function. This report describes the overall computer model (e.g., its deterministic and stochastic modes of calculation) and examines the individual submodels used to quantify the debris population in LEO. Model results are compared to observed debris data. Specific recommendations and possible model improvements are cited. Also presented is a sample satellite constellation hazard assessment using EVOLVE. (MM)